The present invention relates to processes for making carbon black and, more particularly, to methods and apparatus for recovering carbon black trapped within a matrix of fiberglass strands.
Ecology and the recovery of recyclable materials as a replacement for the use of natural raw materials has increased greatly in the last decade. As a beneficial side benefit, such recovery and recycling also eliminates the necessity for disposing of waste materials.
One such recovery method is shown in the U.S. Pat. No. 4,038,100 to Haberman entitled, "CHAR COMPOSITION AND A METHOD FOR MAKING A CHAR COMPOSITION". In this patent, it is disclosed how a useful char composition can be produced from rubber containing polymeric hydrocarbons and carbon black by pyrolyzing and grinding such rubber with heated balls for a sufficient length of time to vaporize and depolymerize the hydrocarbons and to produce a solid char material having a very fine particle size. The char thus produced is free of non-decomposed rubber and coke and has a benzine discoloration number of greater than 70% and preferably 90%. The source of the rubber as primarily visualized by Haberman is tires such as those on automobiles, trucks, and the like.
Since many of the tires produced today contain fiberglass and/or steel belting materials, the char produced by the method of Haberman contains unwanted fiberglass and steel particles which must be removed. The steel particles are easily removed by magnetic means to be recycled. The fiberglass is removed by passing the char over a fine mesh screen through which the extremely fine carbon black particles may pass but whereupon the fiberglass particles are trapped forming a fiberglass mat of, typically, one to four inches in thickness.
These mats as removed from the filter screen from the Haberman process represent a presently waste by-product containing two potentially useable components, fiberglass and carbon black. The mats typically contain from 30 to 50 percent fiberglass and 50 to 70 percent carbon black. It is the object of the present invention to provide a method and apparatus for recovering these two potentially useful by-products and eliminating the mats as a waste by-product of the Haberman process.